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#include <fcntl.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <unistd.h>
#include <stdlib.h>
#include <math.h>
char *pname;
char *in_file;
#define DATA_COUNT (1024*1024)
double data_items[DATA_COUNT];
int num_data_items = 0;
#define BUFSIZE 1024
char in_buf[BUFSIZE];
static int
compare_double(const void *p1, const void *p2)
{
double val1 = *(u_int64_t *)p1;
double val2 = *(u_int64_t *)p2;
if (val1 == val2)
return 0;
if (val1 < val2)
return -1;
return 1;
}
int
main(int argc, char **argv)
{
FILE *in_fp;
double sum_x = 0;
double sum_sq_x = 0;
double mean;
double std_dev;
int i;
int one_sd = 0;
int two_sd = 0;
int three_sd = 0;
double one_sd_low, one_sd_high;
double two_sd_low, two_sd_high;
double three_sd_low, three_sd_high;
pname = argv[0];
if (argc == 1)
in_fp = stdin;
else {
in_file = argv[1];
in_fp = fopen(in_file, "r");
}
while (fgets(in_buf, BUFSIZE, in_fp)) {
if (num_data_items == DATA_COUNT) {
fprintf(stderr,
"DATA overflow, increase size of data_items array\n");
exit(1);
}
sscanf(in_buf, "%lf", &data_items[num_data_items]);
#if 0
printf("%lf\n", data_items[num_data_items]);
#endif
num_data_items++;
}
if (num_data_items == 0) {
fprintf(stderr, "Empty input file ?\n");
exit(1);
}
#if 0
printf("Total items %lu\n", num_data_items);
#endif
for (i = 0 ; i < num_data_items ; i++) {
sum_x += data_items[i];
sum_sq_x += data_items[i] * data_items[i];
}
mean = sum_x / num_data_items;
printf("\tMean %.4f\n", mean);
std_dev = sqrt((sum_sq_x / num_data_items) - (mean * mean));
printf("\tStd Dev %.4f (%.4f%% of mean)\n",
std_dev, (std_dev * 100.0) / mean);
one_sd_low = mean - std_dev;
one_sd_high = mean + std_dev;
two_sd_low = mean - (2 * std_dev);
two_sd_high = mean + (2 * std_dev);
three_sd_low = mean - (3 * std_dev);
three_sd_high = mean + (3 * std_dev);
for (i = 0 ; i < num_data_items ; i++) {
if (data_items[i] >= one_sd_low &&
data_items[i] <= one_sd_high)
one_sd++;
if (data_items[i] >= two_sd_low &&
data_items[i] <= two_sd_high)
two_sd++;
if (data_items[i] >= three_sd_low &&
data_items[i] <= three_sd_high)
three_sd++;
}
printf("\tWithin 1 SD %.2f%%\n",
((double)one_sd * 100) / num_data_items);
printf("\tWithin 2 SD %.2f%%\n",
((double)two_sd * 100) / num_data_items);
printf("\tWithin 3 SD %.2f%%\n",
((double)three_sd* 100) / num_data_items);
printf("\tOutside 3 SD %.2f%%\n",
((double)(num_data_items - three_sd) * 100) / num_data_items);
/* Sort the data to get percentiles */
qsort(data_items, num_data_items, sizeof(u_int64_t), compare_double);
printf("\t50th percentile %lf\n", data_items[num_data_items / 2]);
printf("\t75th percentile %lf\n", data_items[(3 * num_data_items) / 4]);
printf("\t90th percentile %lf\n", data_items[(9 * num_data_items) / 10]);
printf("\t99th percentile %lf\n", data_items[(99 * num_data_items) / 100]);
}